Résumé
By means of 3D N-Body Contact Dynamics (CD) simulations, we simulate the gravitational accretion of polydispersed grains initially distributed homogeneously inside a spherical cloud. We aim to measure the resulting free surface Particle Size Distribution (PSD) and compare it to the PSD prescribed for the whole system. Our preliminary results show that the resulting aggregate exhibits a similar spatial homogeneous distribution of grains as the initial cloud, meaning that the accretion process does not modify the initial spatial distribution of grains. This implies that, in our simulations, the measured PSD of the free surface is similar to the nominal PSD of the entire granular system only because the initial cloud is also spatially homogeneous. Our simulations also demonstrate the applicability of the CD method to the simulation of "increasingly realistic" granular asteroids.